Metal-casting method and apparatus



Aug 10, 1943. P. M.'PAYNE METAL-CASTING METHOD AND APPARATUS Filed on.7. 1940 2 Sheets-Sheet l 'lm entor': Pearson M Pay/m By #zlormy v Aug.10, 1943. P. M. PAYNE METAL-CASTING METHOD AND APPARATU$ 2 Sheets-Sheet2 Filed Oct. 7, 1940 Pea/son M Payne Patented Aug. 10, 1943 UNITEDSTATES PATENT OFFICE METAL-CASTING METHOD AND APPARATUS Pearson M.Payne, Denver, 0010. Application October '1, 1940, Serial No. 360,089 I7 Claims.

This invention relates to the art of moulding objects and articles frommolten metal in chilltype moulds, and has as an object to provide animproved method and means whereby metallic articles and objects may bemoulded with enhanced speed, efficiency, and accuracy.

A further object of the invention is to provide an improved method andmeans continuously operable to form metallic castings of high qualityand uniformity.

A further object of the invention is to provide an improved method andmeans continuously and advantageously operable for the rapid andeconomical production of compact, homogeneous, uniform grinding ballssubstantially free from pipes, cavities, and comparable faultscharacteristic of moulding operations.

A further object of the invention is to provide an improved method andmeans operable to maintain a shrinkage head of molten metal in feedingrelationwith castings formed in chill-type moulds until cooling andsolidification of such castings is substantially complete.

'A further object of the invention is to provide an improved,continuously-operable apparatus for the casting of grinding'balls andcomparable improved means automatically operable to normally maintainseparable chill-type mould sec-- tions in cooperating relation in acasting machine. A further object of the invention is to provide animproved ball-casting machine compact in form, susceptible of convenientand inexpensive installation and operation, which is characterized byhigh production at low cost, which requires a minimum of maintenance andattention for eflicient operation, and which is productive of finishedcastings of high quality.

- My invention consists in the construction, arrangement,and'combination of elements hereinafter set forth, and in the methodsand operative phases hereinafter described, all as pointed out in myclaims and illustrated by the accompanying drawings in which' Figure 1is a half-plan view of an improved ball-casting machine embodying theprinciples of my invention and susceptible of operation to give effectto my improved method. Figure 2 is a vertical section taken axially ofthe improved machine substantially on the indicated line 22 of Figure 1.Figure 3 is a side elevation of the improved machine as operativelyinstalled and at substantially right angles to the showing of Figure 2.Figure 4 is a fragmentary, detail section, on an enlarged scale, throughadjacent mould units in position to receive molten metal.

As shown in the drawings, the numeral I 0 designates a preferablycircular, skeletonized, and suitably braced base member, preferablyformed of metal by casting or moulding as an integral unit, and adaptedto be disposed in bearing relation against a supportingsurface for theoperative support of the other elements constituting the apparatus. Themember Ill is formed with ly receive and fit. closely about that portionof the shaft ll immediately above the base member In, and said hub I3 isformed with a radially-extending, somewhat conical flange l4 adjacentits lower relation upwardly from the flange I 4 adjacent,

but somewhat below, the upper end of the hub sleeve. The hub I3 isadapted to be supported by the base member ill for rotation about theshaft II, and to this end outer circular portions of the base memberupper surface and the hub flange lower surface are brought into closeproximity and arranged for engagement against anti-friction devices l6disposed there to facilitate rotation by said hub member relative tosaid base member. A worm gear I! is formed on or secure- 1y fixed to andabout the periphery of the hub flange M for meshing engagement with ahorizontal-disposed worm l8 rotatably carried in suitable bearingsformed for that purpose adjacent one margin of the base member In, and adriving shaft 19 is suitably engaged with the worm l8 to connect thelatter with a source of power, not shown, whereby said worm may berotatively driven to rotate the hub member l3 at relatively much reducedspeed about the shaft II. An annular plate 20 is secured to and incovering relation with the gear l'! and is disposed for cooperation ofits outer margin with the upper margin of an annular flange 2! whichrises from and circumferentially of the base member 10 in housing andforeign matter while providing a trough wherein suitable lubricant maybeheld and thereby supplied to the gear and anti-friction devices 18. Anannular rib 22 preferably rises from the upper -surface oi? the basemember ID just within the orbit of the anti-friction devices 18, and theupper margin of said rib 22 is freely'received in a suitable recess orannular groove formed for such purposes in the lower surface of theflange l4, said rib and groove serving to prevent escape of lubricantinwardly of the base member and likewise protecting against the entranceof foreign matter to and between the bearing surfaces or the hubassembly and base member.

The hub flange l and upwardly-adjacent portion of the hub 13 aresuitably worked to receive and fixedly support the inner ends of aplurality of identical spokes 23 which arethereto secured inuniformly-spaced, radially-extending relation to receive against theupper surface of their outer ends and fixedly support a ring member 24thereby disposed in concentric relation with the shaft II for rotationabout said shaft with the hub 13. Suitable bracw 25 preferably engagedbetween an outer upper portion of the hub flange l4 and outer portionsof the spokes 23 in stifien and brace the rotatable assembly.

Fixed to and in upstanding relation with the per end, said sections 21having a uniform length such as to close closely against'thecircumferentially-adjacent sections to complete a circular mouldassembly. The mould sections 21 are hollow to facilitate circulation ofa cooling medium,

and the outer vertical face of each such section is formed to presentone-half of the mould impression necessary to form the article to becast. Since the apparatus illustrated is adapted for the casting ofgrinding balls, the mould impression interrupting the vertical face ofeach section 21 will be in the form of a hemisphere, and it is,convenient to make the mould sections 21 of such length as to eachaccommodate two or more identical mould impressions, the numbernecessarily depending upon thesize of the finished grinding ball inrelation to the length of the section 21. In addition to the mouldimpressions, indicated at 28, the sections 21 are formed with one-half 5of a conical throat or feeding neck 29 communicating through the uppersurface of the section 21 with each of the mould impression halves 28.

Secured to the outer portion of the ring member 24, and projectingradially outwardly therebeyond, a hinge member 30 is disposed in radialalignment with each of the bracket units 28 to 0 provide ahorizontally-disposed hinge axis in tangential relation with the ringmember 24 adjacent each of the bracket units 28. A yoked bracket arm 3|is hingedly secured at its lower end to each of the hinge members 30 andextends upwardly from such hinge connection to swing in a vertical arctoward and away from the corresponding bracket unit 23, and each of thearms .3! fixedly supports a mould half or section 32,

7 ends of radial arms 31 which adjustably engage identical with thesections 21, disposed to close against a complementary section 21 andcomplete a mould assembly when the supporting bracket arm 3! is movedinwardly'toward the corresponding unit 26. Each of the mould sections 32is hollow for circulation of coolingfluid therethrough I and is providedin intersecting relation with its vertical face with the mouldimpressions and pouring gate openings necessary for registeringcooperation with the corresponding elements in the mould section 21 forcompletion of the mould form necessary to form and complete the objector article to be cast. Thus, in the, apparatus shown, when the mouldsection 32 is moved into engaging relation of its inner vertical facewith and against the outer vertical face of its complementary mouldsection 21, each such mould assembly includes two spherical cavities anda conical pouring gate communicating through the upper surface of themould assembly with each of said cavities, so that filling of saidcavities with molten metal results in the moulding of two grinding ballsin each mould assembly. To normally maintaineach mould section 32 in normal mould-forming engagement against its complementary mould section 21,and to provide means for actuating each bracket arm 3| about its hingemounting for selective separation of the mould sections 32 and 21, anactuating arm 33 is fixed at its outer end to each of the arms 3! andextends radially and inwardly through a suitable opening formed for suchpurpose in the vertical web of the corresponding bracket unit 26 andacross the upper surface of the ring member 24 to adjustably support acounterweight 34 slidably disposed on and in clampable relation with itsinner extension. The inner end of each arm 33 is normally free andunsupported, so that the counterweight 34 associated with said arm actsto urge the inner end of the arm downwardly and thereby swing thebracket arm 3| about its hinge axis until the mould section 32 carriedby the bracket arm 3! is brought into mould-oompleting engagement withits complementary section 21, such engagement serving to limit downwardtravel of the weight 34 and its supporting arm while said weightmaintains the mould sec tions in interengagement. The actuating arms 33are employed to separate the mould section of their rapective mouldassemblies for discharge or removal of completed castings therefrom at asuitable stage in the operative cycle of the apparatus, and for suchpurpose each of the arms 33 is equipped with a roller 35 disposed forrotation below the inner end of the arm in position to engage and ridealong the upper margin of an arcuate cam track 36 suitably disposedrelative to and in fixed relation with the rotatable assembly. The camtrack 36 is arcuate in plan to conform with the orbit of rotationcontaining the rollers 35, and the cam margin of said track is sodisposed and contoured as to engage and gradually elevate :theroller-equi d inner end of each successive arm 33 and subsequently lower3 mould sections. The cam track 36 may be conveniently supported andpositioned on the outer at their inner ends with an upward extensionments constituting a flow-circulating system for the'purpose specifiedmay be employed in co-. operation with the other elementsof theapparatus, a convenient and practical arrangement constituting such asystem beingillustrated in the drawings. As shown, a supply pipe 38 isformed as a circle of suitable radius which is mounted on and in fixedrelation with the bracket units 26 beneath the mould sections 21 and isoperatively connected with each of said mould sections by means ofbranch pipes 39 so that fluid pressure-fed to the pipe 38 will bedelivered within the hollow portions of all of the mould sections 21.fed to the pipe 38 through a supply line 40 which communicates witheither end of an axial bore 4| formed through the fixed shaft II, theopposite end of saidbore being closed by means paratus is in rotationabout the shaft I I, and the type, which is fixedly supported on thebrackets 53 adjacent the pipe 52 and from whence the fluid is dischargedthrough a pipe 51 communicating through theihub flange l4 within thesump 49. with the arrangement illustrated and above described,acontinuous flow of cooling fluid is maintained through the hollowinterior of the mould sections 21 and 32' while the entire apdesiredlevel of cooling fluid may readily be maintained within said mouldsections by proper positioning of the discharge ends of the fluid inletpipes upwardly within the mould sections, or by regulating the volume offluid inflow relative' to outflow through any suitable means, such asvalves, and the like. Y

The apparatus thus far described constitutes a complete ball-casting.;machine wherein a plurality of separable mould assemblies is mountedand rotatively driven about a fixed axis in such a manner as to maintainthe mould assemblies'in closed relation throughout a major Cooling fluidmay conveniently be of a plug 42, and the fluid received within the bore4| flows through openings or channels 43 disposed radially of the shaftII to open above the hub flange I 5 into a distributing chamber providedbetween the outer wall of the shaft II and an upward cylindricalextension of the hub l3 and sealed against escape of fluid therefrom bymeans of suitable packing rings or glands 44. A pipe 45, or a pluralityof such pipes, com

operatively suitable arrangement of means for municates between thedistributing chamber above described and the pipe 38, so that when fluidunder pressure is supplied through the line 40, such fluid is deliveredto the pipe 38 and thence through the branch pipes 39 to the coolingcompartments of the mould sections 21. To

complete the circulation of fluid through the mould sections 21, each ofsaid sections is provided with an outlet or return flow pipe 46 whichcommunicates with and discharges into a circular conduit 41, ofrelatively large diameter, which is supported by and disposed about thebracket units 26 adjacent the pipe 38, and a discharge hne 48communicates between the conduit 41 and suitable openings formed forsuch purpose in the hub flange 14 to carry flow from the ,conduit 41 toand through said flange l4 for discharge and escape through openings inthe base ill to a sump 49 from whence the fluid maybe discharged towaste or pumped for reuse through the circulating system, an annularflange 50 rising from the base "I to terminate adjacent the undersurface of the hub'flange l4 serving as a bafiie to confine thedischarged fluid away from contact with the gears and bearings of theapparatus mounting; The movable mould sections 32 may be similarlycooled by means of fluid from the distributing chamber which is fedthrough a line or lines 5| to a ring-pipe 52 fixedly supported by meansof brackets 53 beneath and outwardly of said mould sections 32, aflexible portion of their orbit and to automatically separate and againclose said assemblies at any position and to any desired degree relativeto the.

rotational orbit. With the. apparatus rotating at suitable speed, moltenmetal is fed to the mould impressions of the closed mould assemblies atthe proper pointin the orbit of rotation, so

that the'mould impressions are fllled and the resulting casting cooledby circulation of fluid through the mould sections and about, the mouldimpressions, whereafter the mould sections are automatically opened topermit the cooled castings to fall away from the apparatus prior toreclosing of the mould assemblies While any filling the mouldimpressions with metal may be employed in giving eifect to the operativecycle of the apparatus shown and described, a very important feature ofthe invention is found in the particular method of pouring the mouldimpressions 'hereinafter described, particularly since the quality andhomogeneity of the finished castings, as well as the productive speed ofthe apparatus, may be materially influenced by the pouring methodsemployed.

To give mu effect to the principles of the in vention, the improvedball-casting machine, constructed and arrangedas illustrated and abovedescribed, is operatively installed with the axis of the shaft I Iinclined somewhat away from the perpendicular so as to disposethe planeof rotation common to the mould assembly upper surfaces at a small anglewith the horizontal, and

such disposition of the apparatus can conveniently be accomplished byelevating one side of tube 54 connecting each of the coolingcompartments of the sections 32 with the pipe 52. Return flow of fluidfrom the sections 32 is had through flexible tubes 55 to a returnconduit 56, of ring the base l0 without in any way disturbing thesymmetrical relationship of the elements constituting the apparatus.When the apparatus is positioned for rotation about an axis inclinedaway from the vertical, the point of delivery of the molten metal islocated in registering relation above the center hne of the mouldassemblies and approximately degrees in the direction of mould assemblyrotation ahead of or in lead ing relation with the low point of therotational plane; a spout 58 being shown as a means forsupplying moltenmetal to the mould assemblies, which spout is located half way betweenthe high and low points of the orbit of rotation and on that side of theapparatus where the mould assemblies are. ascending as they rotate fromthe low to the high point of the orbit. To receive the molten metal fromthe spout 58 and direct flow thereof through the openings 29 and withinthe mould impressions of the mould assemblies, a pouring trough or track59- is superposed on the mould assemblies in position to receivedischarge flow from said spout. The trough59 is formed of suitablerefractory material, such as sand, vermiculite, and likereadily-mouldable material having low heat conduction properties, in theform 01' sectional units adapted to overlap the joint between adjacentmould assemblies and abut to form a continuing channel wherein themolten metal may flow. The sections of .the trough 59 are formed withopenings adapted to register and. permit communication through thetrough with the openings 29 oi the mould impressions, and said troughopenings are prefer,- ably defined by hollow, frusto-conical necks",formed from the same material as the trough sections and integrally withthe latter, arranged to engage within and line the mould openings 29.The trough sections 59 are supported by the separable sections oi themould assemblies and close over the line of separation between saidmould sections, hence are destroyed when the mould sections areseparated ior release of castings and must be replaced as the mouldassemblies are rotated for recharge. A supply of the trough sections 59is prepared in advance and the successive trough sections are placed inposition on the mould assemblies after the latter have been closed readyfor pouring, so that a number of trough sections 59 are in position toform a trough of considerable length on the mould assemblies approachingthe spout 58.

It is the function of the inclination given to the plane of mouldassembly rotation, in cooperation with the pouringtrough 59 and fillerneck liners 60, to maintain a supply of molten metal adjacent the pointof last cooling of each casting to fill shrinkage voids, pipes, and thelike, for the production of a casting free from faults, of high quality,and uniformity of texture.

This result is accomplished by permitting the molten metal to flow downthe incline of the trough 59 for some distance, filling the mouldcavities traversed, before the apparatus is placed in rotation, andthereafter so adjusting the rate of metal fiow to the speed of apparatusrotation as to successively fill the mould impressions approaching thespout 58 well in advance of their passing under said spout, so that thecompletely filled mould impressions are moved for a distance under thestream of molten metal flow along the trough 59, the low heat-conductingproperties of the trough 59 and liners 60, together with the heat of themolten metal in the trough 59, serving to maintaina supply of metal influid condition in the filler necks on hot tops communicating with themould impressions and hence in position to new into and fill any voids,cavities, and pipes which may develop in cooling of the casting, and atthe same time provide a path of escape for air and other gases whichmight be entrapped within the mould or solidifying metal withundesirable eflect on the finished product.

In the practice of the improved method through the improved apparatusshown and described,

the point of metal feed is located between thehigh and low points'of therotational orbit on that side of the machine where the mould assembliesare ascending, the cam track 36 is arranged to open the mould assembliessome 120 to 180 degrees of rotation after the moulds have passed underthe charging spout and to maintain the mould assemblies open long enoughfor complete discharge of finished castings, and sections of the trough59 are placed in position on the mould assemblies for some .90 degreesof rotation in trailing relation with the spout position, whereaftermolten metal is fed through the spout 58 to the trough 59 and ispermitted to flow down the incline of said trough, filling the mouldimpressions traversed, a distance, perhaps corresponding to three ormore mould sections, best suited to the character and temperature of themetal employed and the type, size and quality oi the casting desired,whereafter the apparatus is set in rotation in a direction such as willbring the poured mould impressions upwardly toward and beneath the spout58 at a speed so adjusted to the rate of metal flow as to maintain thepoint of mould impression pouring in spaced relation downwardly of theincline away from said spout.

.As will be obvious, successive sections of the trough 59 are placed inposition on the rotating reclose they are then ready for a repetition ofthe operative cycle, By this means is provided a simple; rapid, andeconomical method of continuously and repetitiously moulding articles ofmetal with a high degree of uniformity, homogeneity and quality. Thecooperating mould sections may of course carry mould impressions ofarious shapes and sizes, and the metal supplied to fill the mouldimpressions may be of any specific character and alloy suited to theproduction of the castings desired, the adaptation of the method andapparatus to the production of grinding balls being but typical of themany specific applications to which the method and apparatus is adapted.

Since many changes, variations, and modifications in the specific form,construction, and arrangement oi the elements shown and described, maybe had without departing from the spirit of my invention, I wish to beunderstood as being limited solely by the scope of the appended claims,rather than by any details or the illustrative shown and foregoingdescription.

-I claim as my invention:

1. The method of casting metal whichconsists of moving a gang of gatedmoulds along an upwardly-inclined path, providing a continuous pouringtrough on the upper surface or said mould gang in heat-insulatingcommunication through the mould gates, feeding molten metal to saidtrough for gravity flow therealong and consequent successive filling'ofprogressively-lower along an upwardly-inclined path, providing acontinuous pouring trough on the upper surface of said mould gang inheateinsulating communication through the mould gates, feeding moltenmetal to said trough for gravity flow therealong and consequentsuccessive filling of progressively lower mould cavities, and subsequentmoving of the mould gang upwardly past the point of metal feed at a rateof speed such as will maintain the point of mould filling at a gateseveral moulds below the point of metal feed and at the lower end of astream of molten metal in said trough whereunder the filled mouldstravel a considerable distance for escape of gases and filling ofshrinkage cavities during cooling of their contents.

3. The method of casting metal which consists of mounting a gang ofgated moulds in end adjacency for travel along an upwardly-inclined pathbeneath a metal-pouring spout, providing a refractory pouring troughalong the upper surface of said mould gang in heat-insulatingcommunication through the mould gates, feeding metal from said spoutinto said trough for gravity fiow therealong and consequent successivefilling of progressively-lower mould cavities, and subsequently movingsaid mould gang upwardly along its path of travel and beneath said spoutat a rate such as will maintain a stream of molten metal in said .troughfor the filling of mould.

cavities well before their passage under the pouring spout andwhereunder the filled moulds travel a considerable distance for escapeof gases and filling of shrinkage cavities during cooling of theircontents.

4. The method of casting metal which consists of mounting a gang ofgated moulds having a pouring trough on its upper .surface inheat-insulating communication through the mould gates for travel alongan upwardly-inclined path beneath a pouring spout, feeding molten metalfrom said spout into said trough, subsequently moving said mouldgangupwardly along its inclined path beneath said spout, and correlating therate of molten metal flow with the speed of mould travel to maintain astream of metal in said trough for complete filling of the successivemetal fiow and whereunder the filled moulds travel a considerabledistance for escape of gases and filling of shrinkage cavities duringinitial cooling of their contents.

6. In metal-casting apparatus having a turntable rotatable in a planeinclined to the horizontal, means for rotatingsaid turntable, separablemould assemblies ingend adjacency circumferentially of said turntable,and means for automatically opening said mould assemblies as an incidentof turntable rotation and for maintaining said mould assemblies closedduring the ascending portion of their rotational orbit, means forsupplying molten metal to fill the cavities of said mould assemblies,said means comprising frusto-conical gates opening at their larger endsthrough the upper surfaces of the mould assemblies, a pouring troughcarried by said mould assemblies during the ascending portion of theirorbital travel, said trough consisting of a plurality of likeend-abutting sections of heatinsulating, refractory material disposed onthe upper surfaces of the mould assemblies in covering'relation with theparting line between the separable units of each assembly, each of saidtrough sections having a longitudinal channel intersecting its uppersurface, frusto-conical bosses depending from its lower surface toengage within and cover the walls of the corresponding mould gates, anda passage communicating through each of said bosses and with the fiowchannel of its section, and a molten metal delivery spout fixedlypositioned to dischargamolten for rotating said turntable,outwardly-facing mould'sections bracket-supported in end adjamouldcavities well prior prior to their passage under said spout andwhereunder the filled moulds travel a considerable distance for escapeof gases "and filling of shrinkage cavities during cooling of theircontents. I 5. The method of casting metal which consists with the speedof mould travel to maintain a.

stream of molten metal in said trough for succcessive filling of mouldcavities below and well in advance of their passage under the incomingsections, longitudinally-channeled,

cency circumferentially of and above said tumtable, complementary,inwardly-facing mould sections hingedly supported for actuation througha verticai are into and out of registration with said fixed mouldsections, means operable as an incident of turntable rotation tomaintain the mould sections of each pair in closed registration duringascending travel of the turntable and to separate the mould sections ofeach pair for discharge of their contents during descending travel ofsaid turntable; pouring gates formed in and opening through the uppersurface of said mould pouring trough sections, each formed with anapertured boss adapted to engage and seat within the pouring gates ofthe mould assemblies, disposed in end-abutting relation on 'the closedmould assemblies during ascending travel of the latter, and means forfeeding molten metal to the trough formed by said sections.

PEARSON M. PAYNE.

refractory

